After eleven weeks of on-orbit checkout and verification and a series of orbital ascent maneuvers, the Terra Spacecraft reached its final orbit on February 23. This event was a culmination of years of work for the Terra team with the acquisition Terra’s first engineering images. Terra’s spacecraft subsystems continue to perform flawlessly, with almost all systems now in their operational science mode. Terra’s ground system is providing excellent support for spacecraft command and control, and is performing nominally for the capture and processing of Terra data.
"We’re very excited to see the first engineering images from Terra," said Dr. Yoram Kaufman, Terra project scientist at NASA Goddard Space Flight Center. "They show that the Terra instruments, with their delicate optics and electronics, made it safely to space. The images give us a glimpse of the unprecedented clarity and richness of the data that we anticipate from Terra in the months and years to come. With these data, Terra starts a revolution in Earth Sciences by observing simultaneously many of the processes in land, ocean and atmosphere that form the Earth System in which we live."
"Terra’s final ascent maneuvers were successfully performed," said Kevin Grady, Terra project manager at NASA’s Goddard Space Flight Center, Greenbelt, Md. "Terra is now flying on the World Reference System (WRS), on the same ground track as Landsat 7. Following the initial orbit raising attempt, the Terra team developed a revised plan with eight maneuvers required to raise Terra’s orbit. Each maneuver was performed as planned.
"This performance demonstrates the quality and commitment of the entire Terra Operations Team. Everyone involved deserves congratulations for the successful ascent of Terra to its operational orbit," Grady added.
On February 24, the Moderate-resolution, Imaging Spectroradiometer (MODIS) opened the Earth view door during a pass over eastern North America. The acquisition of science data on board proceeded nominally, and the initial MODIS measurements were successfully downlinked and captured on the ground. The initial image produced by the MODIS Team is a spectacular color image of eastern North America, extending from Canada down through Mexico.
"A ‘first light,’ engineering quality, swath of MODIS data over eastern North America reveals that the instrument is working quite well," said Dr. Vince Solomonson, principal investigator for the MODIS instrument. "These data corroborate that MODIS will provide global, daily, multispectral simultaneous observations of land, ocean, and atmospheric features that will improve substantially our understanding of how the Earth works as a system. Unprecedented views of ocean fluorescence, the intensity of fires over land and eruptions of volcanoes, and properties of clouds (e.g, the extent of cirrus clouds) will be forthcoming. MODIS is designed to play a significant role as the Terra mission provides a comprehensive assessment of the state of the planet Earth."
Later that morning, the Multi-angle Imaging SpectroRadiometer (MISR) Team opened their instrument cover over central Canada. Again all operations proceeded as planned. Shortly thereafter, the MISR Team produced a spectacular image over Ontario, Canada.
"These first pictures illustrate many of MISR’s new and unique capabilities," said MISR Principal Investigator Dr. David J. Diner of NASA’s Jet Propulsion Laboratory. "The instrument, operations system, and science data processing software are performing extremely well and the quality of the images, particularly at the very challenging oblique angles, is outstanding."
As the week was ending, the Clouds and the Earth’s Radiant Energy System (CERES) Team had just completed opening the contamination cover on the CERES aft and fore instrument. Once again, the activation of the cover was nominal. Later in the day, the instruments were configured in the normal mission mode, with one sensor in crosstrack mode, and one in the biaxial mode.
"Both instruments are on and appear to be working very well," said Dr. Bruce Barkstrom, principal investigator for the CERES Instrument at NASA Langley Research Center. "In normal operation one instrument will scan perpendicular to the Terra ground track, in order to spatially sample the Earth. The other instrument samples the angular distribution of radiation. These two Terra instruments join a previous CERES scanner on the Tropical Rainfall Measuring Mission (TRMM), which was launched on November 27, 1997. They complement TRMM by extending the observations to cover the globe and by improving sampling of the large diurnal cycle of radiation."
The Advanced spaceborne thermal Emission and Reflection Radiometer (ASTER) completed imaging over Japan on February 24.
The week of February 27, the Measurements of Pollution in the Troposphere (MOPITT) instrument doors were opened. Later that week, MOPITT’s coolers were commanded on and they began collecting science data.
After a little over two months on-orbit, Terra is beginning to produce spectacular imagery. Operationally, Terra will produce 6 terabytes (6 trillion bytes) of data every month, all of which will be available to users for many purposes including science research, applications, and education. The first release of Terra Science imagery is expected for mid-April 2000.